System for adaptively generating signal in alternate formats as for an EDTV system

ABSTRACT

A video signal generating system develops an encoded video signal representing less than all of the video information. Auxiliary signal generating circuitry develops a pair of auxiliary signals representing in part the remaining video information. A first of the pair of auxiliary signals includes relatively high fidelity signal but with limited bandwidth. The second auxiliary signal includes relatively low fidelity information but has an effective higher bandwidth. Depending upon the information density of the auxiliary information, the first and second auxiliary signals are selected to produce an auxiliary output signal which is combined with the encoded video signal for transmission. A receiver responsive to the transmitted signal separates the video and auxiliary signals. The video and auxiliary signals are decoded and used to generate enhanced display images.

This invention relates to a system for changing the form of a signal tobe transmitted, responsive to a feature of the signal.

BACKGROUND OF THE INVENTION

The invention will be described in the environment of an enhanceddefinition television (EDTV) system, however it is not to be construedas limited to this application.

The television industry is striving to improve the quality of displayedtelevision images. To this end several EDTV and high definitiontelevision (HDTV) systems have been proposed. The EDTV systems developbroadcast signals which are compatible for reception by existingstandard receivers, but contain auxiliary signal components which may beutilized by EDTV receivers to generate enhanced images. The HDTV systemsgenerate broadcast signals for producing high resolution, wide aspectratio images on HDTV receivers, which signals are not compatible forreception by current day "standard" receivers. In both the EDTV and HDTVsystems, in general it is necessary, either for regulatory reasons orpragmatic reasons to encode the original source image signals in afrequency spectrum of bandwidth narrower than the bandwidth of thesource signals. Typically the encoding formats are established accordingto some statistically average signal feature whereby for the majority oftransmitted images the respective receiver will be capable of faithfullyreproducing the original image. However for certain images, for examplethe bandwidth of a particular encoded signal component may beinsufficient and result in a poorer quality reproduced image. As anexample consider the EDTV system described by Isnardi et al., entitled"Decoding Issues In the ACTV System", IEEE Transactions on ConsumerElectronics, Vol. 34, No. 1, February 1988, pp. 111-120, also describedin U.S. patent application Ser. No. 139,340, filed 29 December 1987 andincorporated herein by reference. The Isnardi et al. system develops anauxiliary signal component designated the vertical-temporal (V-T) helpersignal, to aid the receiver in converting interlace scan signals toprogressive scan signals.

The encoder of the Isnardi et al. system utilizes a progressive scansource of image signals and generates an interlace scan broadcast signalNominally video signals contain significant information redundancy Dueto this redundancy, receivers can be designed to autonomously convertinterlace scan signals back to progressive scan signals fairlyaccurately. For images representing moving objects, the amount ofredundancy diminishes and the ability of a receiver to autonomouslyconvert interlace scan signals to progressive scan signals is impairedbecause the receiver lacks sufficient information. The V-T helper signalwhich has a variable amplitude provides this information. Since thehelper signal represents only the receivers prediction error, itcontains relatively low average energy for a majority of images. Thebandwidth of the helper signal is limited to 750 κH2 to facilitateencoding, which bandwidth is sufficient to provide a helper signal withadequate information to reconstruct a majority of images. However thebandwidth is too narrow to provide sufficient helper information forimages containing a high degree of detail and images which are panned.Consequently, the system performance may be deficient for a sequence ofa certain class of images.

SUMMARY OF THE INVENTION

The present invention ameliorates the deficiencies of bandwidthlimitations by providing for alternate signal formats wherein a firstformat sacrifices bandwidth for signal fidelity and a second formatsacrifices signal fidelity for effective broader bandwidth. In oneembodiment of the invention, included in the transmitting end of asignal processing system, first and second signal encoders respond to asignal component of interest. The first encoder generates an encodedauxiliary signal in a first format having relatively high fidelity overa given bandwidth. The second encoder generates an encoded auxiliarysignal in a second format which is coarsely quantized and datacompressed to provide an effective wider bandwidth. A detector,responsive to the signal component, determines the energy or informationdensity of the component, and provides auxiliary signal from the firstand second encoders to transmitting circuitry for low and high energydensity signals respectively.

In a further embodiment, included in the receiving end of a signalprocessing system, first and second decoders for decoding signal encodedin said first and second formats respectively are arranged to processthe received auxiliary signal. A detector responsive to the receivedauxiliary signal determines the format of the received signal andprovides signal from the appropriate decoder to further processingcircuit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a dot pattern representing in part, horizontal lines ofprogressively scanned video signal from several fields/frames, useful indescribing the invention.

FIG. 2 is a block diagram of circuitry for generating a progressive scanhelper signal.

FIGS. 3 and 4 are block diagrams of alternative apparatus embodying theinvention including circuitry for encoding helper signals in two formatsand circuitry for decoding such signal.

DETAILED DESCRIPTION

Referring to FIG. 1 each column of dots represents a portion of thenumber of horizontal lines of video signal scanned in 1/60th of a second(NTSC format). For purposes of this description, the lines scanned in1/60th of a second (one column of dots) whether in interlace scan formor progressive scan form, will be designated a field interval. Thus FIG.1 represents a portion of four fields designate F_(N-1) to F_(N+2). Afield including both the filled dots and the open circles represents aprogressive scan image. A field including only the filled dotsrepresents one field of a frame of interlace scanned image.

In the system described in the aforementioned Isnardi et al. reference,at the transmitting end of the system, video signal from a progressivescan source is converted to interlace form for broadcasting. In effectthis is accomplished by deleting alternate lines in alternate fields.With reference to FIG. 1 the lines represented by circles are deletedand the lines represented by solid dots are transmitted. At the receiverthe deleted lines are reconstructed to regenerate a progressive scanvideo signal. To aid the receiver in reconstructing the deleted lines ahelper signal is generated at the broadcast end and transmitted with thebroadcast signal. The helper signal is an interlace signal and includesa predictive error that the receiver would make in autonomouslyreconstructing the moving lines. For example the receiver will haveinformation corresponding to lines A_(i) and B_(i) from fields F_(N) andF_(N+2) respectively. Without a helper signal the receivers couldreconstruct the missing line x_(i) according to the algorithm x_(i)=(A_(i) +B_(i))/2 where x_(i), A_(i) and B_(i) represent signalamplitudes. However the calculated value x_(i) may be significantly inerror. To preclude such error, the Isnardi et al. system generates ahelper signal at the transmitter according to the relation

    helper=x.sub.i -(A.sub.i +B.sub.i)/2                       (1)

At the receiver the helper signal is added to the respective values(A_(i) +B_(i))/2 to accurately generate the missing lines. Because ofthe high level of redundancy in most images and sequences of images thehelper signal is zero valued much of the time and therefore can betransmitted with relatively narrow bandwidth. Based on this assumption,the Isnardi et al. system band limits the helper signal to 750 kHz andtransmits it with the encoded luma/chroma components by quadraturemodulation of the picture carrier In order to prevent interference withthe encoded luma/chroma components, the helper signal is amplitudecompressed before modulation. The compression however has the undesiredeffect of reducing the signal-to-noise ratio of the helper signal at thereceiver. In the following description, a first embodiment, withreference to FIG. 3, overcomes the bandwidth limitations on the helpersignal, and a second embodiment, with reference to FIG. 4 overcomes boththe bandwidth and signal-to-noise limitations.

Refer now to FIG. 2 which shows circuitry for generating signalsemployed by the signal formatters of FIGS. 3 and 4. The FIG. 2 circuitrygenerates three signals, S1, S2 and S3. Signal S1 corresponds to thehelper signal generated in the Isnardi et al. apparatus. In FIG. 2 aprogressive scan luminance input signal, assumed to be a sampled datapulse code modulated signal, is coupled to a divide-by-two scalingcircuit 26 and the cascade connection of delay elements 10, 12, 14 and16. Delay elements 10 and 16 each delay signal by 524 horizontal lineperiods and delay elements 12 and 14 each delay signal by one horizontalline period. Output signal from delay element 16 is coupled to adivide-by-two scaling circuit 24. Output signals from scaling circuits24 and 26 are coupled to respective input connections of an addercircuit 18. If the current input signal coupled to delay element 10corresponds to line B_(i) in FIG. 1, then the output signals from delayelements 10, 12, 14 and 16 represent lines C_(i+1), x_(i), C_(i) andA_(i) respectively. Consequently, adder circuit generates the sums(A_(i) +B_(i))/2. These sums are coupled to the subtrahend inputconnection of a substracter circuit 20. Signal representing horizontalline x_(i) from the output of delay element 12 is coupled to the minuendinput connection of the subtracter circuit 20 which generates thetemporal differences x_(i) -(A_(i) +B_(i))/2. These differences are inprogressive scan format and only alternate lines are of interest. Hencethe signal from subtracter 20 is applied to a progressive scan tointerlace scan converter 44, which selects alternate lines of signalrepresenting lines which are deleted and time expands them to interlacescan intervals to generate the signal S1.

Signals representing horizontal lines C_(i+1) and C_(i), from delayelements 10 and 14 respectively, are coupled to respective inputconnections of adder circuit 34 via divide-by-two scaling circuits 28and 30. Adder circuit 34 generates the sums (C_(i+1) +C_(i))/2. Outputsums from adder 34 are coupled to the subtrahend input connection of asubtracter circuit 32. Signal representing lines x_(i) is coupled to theminuend input connection of subtracter 32 which generates the verticaldifferences

    x.sub.i -(C.sub.i+1 +C.sub.i)/2.

Temporal differences from the subtracter 20 and vertical differencesfrom the subtracter 32 are coupled to respective magnitude determiningcircuits 40 and 36. The magnitudes of the vertical and temporaldifferences are coupled to a comparator shown as a subtracter circuit38. Comparator 38 is arranged to generate a logic one value for themagnitudes of the vertical differences being smaller than the magnitudeof the temporal differences and a logic zero value for the magnitude ofthe temporal differences being the smaller.

Output signal from comparator 38 is coupled to the progressive scan tointerlace scan converter 44, wherein the alternate lines of signalcorresponding to the deleted lines are time expanded to produce signalS2. In addition, the output signal from the comparator 38 is coupled tothe control input connection of the multiplexing switch 42. The temporaland vertical difference signals are coupled to respective signal inputconnections of switch 42, which, responsive to the comparator signal,provides the smaller of the temporal and vertical differences on e.g. apixel by pixel basis. Output signal from the switch 42 is applied to theconverter 44 wherein signal representing deleted lines is time expandedto generate signal S3.

Signal S3 which corresponds to the smaller of successive vertical andtemporal differences tends to be lower in amplitude than signal S1 thusrequiring lesser compression and lesser bandwidth to convey theinformation.

Refer now to FIG. 3 which provides an auxiliary or helper signalformatted as an analog representation of the temporal differences S1, oralternatively as an indication of whether vertical or temporalinterpolations (signal S2) will produce a more accurate reconstructedline in the receiver. The criterion for selecting the helper signalformat is the energy or information density of signal S1. If signal S1,when band limited to 750 kH2, will provide sufficient information toreconstruct the deleted lines in the receiver, signal S1 is transmitted.If not, then signal S2, which is a bilevel signal, is compressed usingfor example run length encoding or statistical (Huffman) encoding, or acombination of both and transmitted.

Signal S1 is coupled to the digital-to-analog converter (DAC) 300 whereit is converted to analog form. DAC 300 may be a multiplying converterand arranged to provide amplitude compression. Output signal from DAC300 is applied to a signal information density or energy detector 304and to the compensating delay element 306. Delay element 306 provides adelay interval equal to the intervals over which detector 304 providesenergy calculations and may equal a horizontal line interval, a fieldinterval or a frame interval for example. Detector 304 may be of thetype described in U.S. Pat. No. 4402013 entitled "Video SignalAnalyzer," which counts the number of signal transitions that exceed apredetermined amplitude over a predetermined interval. If the number oftransitions exceeds a preset value detector 304 provides a logic oneoutput signal for the duration of the interval, otherwise it provides alogic zero output signal. Note detector 304 may be realized with digitalapparatus in which case it will be connected ahead of the DAC 300. Theoutput signal from detector 304 is applied to control a switchingcircuit or multiplexer 310. In an alternative embodiment energy detector304 may comprise a counter coupled to count pulses of the signal S2 overa predetermined interval, and provide an output if the number of pulsesexceeds a predetermined number.

Analog signal S1 from delay element 306 is coupled to a first signalinput terminal of multiplexer 310, the output of which is coupled to thelow pass filter 312 having a cutoff frequency of e.g. 750 kHz.

Signal S2, which indicates whether a vertically interpolated or atemporally interpolated signal will more accurately represent signalsrepresenting deleted lines is coupled to an encoder 302. Encoder 302 mayinclude a run length encoder followed by a statistical (such as Huffman)encoder to compress the signal S2. Output signal from encoder 302 iscoupled to a second signal input terminal of multiplexer 310 via acompensating delay element 308 if required.

Multiplexer 310, in response to the output signal from detector 304couples the analog signal S1 to low pass filter 312 if the energydensity of signal S1 is less than a predetermined level and couplescompressed signal S2 to the low pass filter 312 if the energy density ofsignal S1 exceeds the predetermined level.

The signal from low pass filter 312 is applied to one input terminal ofa signal combiner 316. Video signal, such as a standard NTSC signal orvideo signal from, for example, an Isnardi et al. type EDTV encoder,from a source 314 is coupled to a second signal input terminal of signalcombiner 316. Signal combiner 316 may be of the type which quadraturemodulates the respective input signals onto a picture carrier.Alternatively source 314 may be a source of HDTV signals and signalcombiner 316 may include circuitry to combine the input signals in MACformat. Combined output signal from signal combiner 316 is then appliedto a transmission channel such as a broadcast transmitter, cable etc.

At the receiving end of the system, received signal is applied to asignal separator 320 which performs the complementary function ofcombiner 316. For example if combiner 316 is a quadrature modulator,then separator 320 is a quadrature demodulator. Separator 320 separatesthe helper signal from the encoded video signal. The separated videosignal is coupled to a video decoder 322 which provides separatedluminance, Y, and chrominance, C, signal components in interlace scanformat. The chrominance component, which may be represented by I and Qcolor difference signals, are coupled to an interlace-to-progressivescan converter 324. Converter 324 may be simple speed up circuitry whichrepeats each line of chrominance signal at the progressive scan rate.The chrominance output signals, from converter 324, are coupled tomatrix circuitry (not shown) wherein they are combined with progressivescan luminance signal to generate R, G and B color signals to drive adisplay device.

The separated luminance component signal from decoder 322 is coupled toan adaptive interlace-to-progressive scan converter including theremainder of the circuitry in FIG. 3. The luminance signal is applied tothe cascade coupled delay elements 326, 328 and 330 which delay signalsby 262, 1 and 262 interlace scan intervals respectively. If the currentsignal output from decoder 322 corresponds to line B_(i) in FIG. 1, thenthe output signals from delay elements 326, 328 and 330 correspond tosignals from lines C_(i+1), C_(i) and A_(i) respectively. The outputsignal C_(i) from delay element 328 is applied to a speed up circuit 332which time compresses the interlace line scan signal to a progressiveline scan interval. The time compressed signal provided by speed upcircuit 332 is coupled to one signal input terminal of a multiplexer362.

The signals C_(i) and C_(i+1) from delay elements 328 and 326 arecoupled, via divide-by-two weighting circuits 336 and 338, to respectiveinput terminals of an adder circuit 342. The adder circuit 342 producesthe sums (C_(i) +C_(i+1))/2 which are coupled to one signal inputterminal of a multiplexer 356. The sums (C_(i) +C_(i+1))/2 correspond tovertically interpolated samples representing deleted lines.

The signals A_(i) and B_(i), from delay element 330 and decoder 322 arecoupled, via divide-by-two weighting circuits 334 and 340, to respectiveinput terminals of an adder circuit 344. The adder circuit 344 producesthe sums (A_(i) +B_(i))/2 which are coupled to a second signal inputterminal of the multiplexer 356. The sums (A_(i) +B_(i))/2 correspond totemporally interpolated samples representing deleted lines.

The multiplexer 356 is controlled by signal from an OR gate 354 to applyone of the vertically or temporally interpolated signals to an inputterminal of an adder circuit 358. The adder 358 provides interpolatedsignals representing deleted lines of interlace scan duration to a speedup circuit 360 which time compresses the interpolated lines toprogressive scan intervals. Time compressed signals from speed upcircuit 360 are coupled to a second signal input terminal of themultiplexer 362. The multiplexer 362 is controlled by a square wavesignal of interlace scan line rate to alternately couple time compressedreal lines C_(i) and time compressed interpolated lines from speed upcircuit 360 to its output terminal. The luminance output signal providedby the multiplexer 362 is coupled to the aforementioned matrix circuitryto be combined with the chrominance signal from converter 324.

In the receiver circuitry so far described it is presumed that decoder322 includes analog-to-digital converter circuitry to convert thereceived video signal to digital, e.g., PCM format and that theprocessing circuitry is of digital design.

The auxiliary or helper signal from signal separator 320 is coupled to adecoder 346, a digital detector 348 and an analog-to-digital converter(ADC) 350. The decoder 346 performs the complimentary function of theencoder 302 at the transmitting end of the system. Decoder 346 mayinclude a statistical (e.g. Huffman) decoder followed by a run lengthdecoder, and provides the signal S2 to one input terminal of the OR gate354. For logic one and logic zero level values provided by the decoder346 the multiplexer 356 is conditioned to pass the temporally andvertically interpolated values respectively.

The digital detector 348 determines whether the helper signal is thedigitally compressed signal S2 or the analog helper signal S1. This maybe accomplished by having the encoder 302 include a recognition signalat the beginning of each interval of encoded compressed signal. In thisinstance the digital detector may be a correlator designed to recognizethe recognition signal and output a zero level for the followinginterval. For intervals in which no recognition signal is detected, thedigital detector 348 provides a logic one level output signal. Thisfunction may be incorporated within the decoder 346. Alternatively thecompressed signal S2, at the beginning of each interval, will ofnecessity include a relatively dense bit stream to initiate the decoder.This bit stream will nominally include far more transitions than theanalog helper signal. The digital detector 348 may be designed todifferentiate the analog and compressed signal formats by countingsignal transitions at the beginning of each interval. Since the systemwill typically be designed to format the alternative signals inintervals of line, field or frame periods it is a straight forwardprocess to synchronize the detector to the beginning of each intervalusing the horizontal or vertical synchronizing components of the videosignal.

The output signal from the digital detector is coupled to a second inputterminal of the OR gate 354 and to the control input of a multiplexer352. The analog helper signal after conversion to PCM form in ADC 350 iscoupled to one signal input terminal of multiplexer 352. A zero valuedsignal is coupled to a second input terminal of the multiplexer 352. Ifthe received helper signal is the analog signal, digital detector 348produces a logic one output signal which conditions the multiplexer 356to couple the temporally interpolated values to the adder 358 andconditions the multiplexer 352 to couple the PCM helper signal from ADC350 to a second input terminal of adder 358. In this instance, thesignal provided by adder circuit 358 is the sum of the helper (x_(i)-(A_(i) +B_(i))/2) plus the temporally interpolated signal (A_(i)+B_(i))/2) which represent the detected lines x_(i) exactly.Alternatively, if the received helper signal is the compressed digitalsignal S2, digital detector 348 provides a logic zero valued outputsignal which conditions the multiplexer 352 to couple a zero value tothe adder 358. In this instance the multiplexer 356 is controlled by theoutput of decoder 346 and provides to adder 358 the vertically ortemporally interpolated signal which most accurately represents thedeleted lines.

The FIG. 4 circuitry generates alternative helper signals which are bothformatted in compressed digital form. The all digital helperalternatives require a significantly smaller dynamic range than theanalog helper and thus create significantly less likelihood ofinterference with the combined video signal. In the FIG. 4 circuit,elements designated with like numbers as elements in FIG. 3 are similarelements and perform similar functions.

Signal S2, which indicates which of the vertically and temporallyinterpolated signals will provide the more accurate representation ofthe deleted lines at the receiver, and which indicates which of thesignal differences from subtractors 20 and 32 of FIG. 2 is smaller, iscoupled to the input terminal of an encoder 400. Encoder 400 may besimilar to encoder 300 in FIG. 3 and may include a run length encoderfollowed by a statistical encoder. Encoder 400 also includes apparatusto insert a recognition code at the beginning of each coding interval.The compressed signal S2 from encoder 400 is coupled to one signal inputterminal of a multiplexing switch 410 via a compensating delay element404.

Signal S2, which is a single bit signal, is appended as, for example, aleast significant bit to samples of signal S3 which occurs as multibitsamples. In the combined S2-S3 signal the S2 bit identifies if the S3sample represents a vertical or temporal difference error. The combinedS2-S3 signal is coupled to an encoder 402 which provides a digitallycompressed S2-S3 signal. Encoder 402 may include a run length encoderfollowed by a statistical decoder. In addition, it includes apparatus toinsert a recognition code at the beginning of each coding interval. Thecompressed signal S2-S3 is coupled to a second signal input terminal ofthe multiplexer 410 via compensating delay element 406.

A counter 408 is coupled to receive the compressed S2-S3 signal andcounts the number of signal bits in a predetermined interval, e.g., aline interval, a field interval, etc. If the counted value exceeds anumber which has been determined to exceed the channel capacity(auxiliary channel), counter 408 generates a logic one output signal forthe coding interval. The output from counter 408 is coupled to controlthe multiplexer 410. If the number of bits of the compressed S2-S3signal is lesser or exceeds the channel capacity, the counter conditionsthe multiplexer 410 to pass the compressed S2-S3 signal or thecompressed S2 signal respectively. Note the delay elements 404 and 406provide sufficient signal delays for the counter 408 to completedetection over a coding interval before the compressed signals arrive atthe multiplexer 410. Note also that the signal S3, always represents thesmaller of the vertical and temporal differences and thus signal S3 canbe represented by fewer bits than were either only the vertical ortemporal differences utilized as the error signal.

The output signal from multiplexer 410 is coupled to the signal combiner414 wherein it is combined with video signal from e.g., an EDTV encoder412. The signal combiner 414 may be a quadrature modulator whichquadrature modulates a picture carrier with the respective input signalsthereto.

At the receiving end of the system the auxiliary or helper signalprovided by signal separator 320 is coupled to first and second decoders422 and 426 and to a code type detector 424. The code type detector 424is responsive to the inserted recognition codes and generates signalswhich are applied to the enable, E, terminals of the first and seconddecoders 422 and 426, to enable the appropriate decoder.

The decoder 422 performs the complementary function to encoder 400 andprovides the signal S2 spatially correlated with the interpolated valuesprovided by adder circuits 342 and 344. The decoded signal S2 is coupledto one input terminal of the OR gate 428 to control the multiplexer 356when decoder 422 is enabled.

The decoder 426 performs the complementary function to encoder 402 andprovides the combined signal S2-S3 spatially correlated with theinterpolated values from adder circuits 342 and 344. The signal S2 bit,of the combined decoded S2-S3 signal, is coupled to a second inputterminal of the OR gate 428 to control the multiplexer 356 when decoder426 is enabled. The bits representing signal S3 of the decoded S2-S3signal are coupled to the adder 358 when decoder 426 is enabled and azero value is coupled to adder 358 when decoder 426 is disabled.

If the received helper signal corresponds to the signal S2 format, thedecoder 422 conditions (with signal S2) the multiplexer 356 to pass thevertical or temporal interpolated signal which will most closelyrepresent the deleted lines. This signal is coupled unchanged, via adder358, to the speed up circuitry 360. Alternatively, if the receivedhelper signal corresponds to the S2-S3 signal format, the S2 signal fromdecoder 426 conditions the multiplexer 356 to pass the vertically ortemporally interpolated signal which most closely represents the deletedlines to adder 358. The error signal S3 from decoder 426 is added inadder 358 to the signal provided by the multiplexer 356. The sumsprovided by adder 358, in this instance, exactly represent the signalsof the deleted lines.

In the foregoing description and figures, compensating delay elementshave been omitted to avoid confusion. For example, if the video decoder322 is an EDTV decoder of the Isnardi et al. type, it may be necessaryto include a compensating delay in the helper signal path to correlatethe helper and video signals. In addition, it may be necessary toinclude compensating delays between the signal separator 320 and thedecoders 422 and 426 to provide the code type detector 424 time toidentify the signal format before the helper signal is applied to therespective decoder. In addition, since the signal c_(i) from delayelement 328 and the generated signal x_(i) from adder occursubstantially concurrently, the time compressed versions of signalsc_(i) and x_(i) will occur concurrently. Therefore an offset delay ofone half an interlace scan line interval must be provided betweencircuit 360 and multiplexer 362. However, one skilled in the art ofcircuit design will readily appreciate where compensating delays arerequired and be able to include them.

What is claimed is:
 1. A system for generating a television signalcomprising:a source of video signal information; means responsive tosaid video signal information for providing an encoded video signal,said encoded video signal excluding a portion of said video signalinformation; means responsive to said video signal information forproviding a first auxiliary signal conveying information related to saidexcluded portion of said video signal information, in a first signalformat; means responsive to said video signal information for providinga second auxiliary signal conveying information related to said excludedportion of said video signal information, in a second signal format;means responsive to one of said first and second auxiliary signals forselectively providing said first auxiliary signal or said secondauxiliary signal, as an auxiliary output signal, depending on theinformation density of said one of said first and second auxiliarysignals; and means for combining said auxiliary output signal and saidencoded video signal to produce said television signal.
 2. The systemset forth in claim 1 wherein said first auxiliary signal is an analogsignal and said second auxiliary signal is a digital signal.
 3. Thesystem set forth in claim 1 wherein said source provides progressivescan luminance signal and said means for providing encoded video signalprovides interlace scan video signal and wherein said means forproviding a first auxiliary signal includes:delay means responsive tosaid progressive scan luminance signal for concurrently providing first,second and third luminance signals representing temporally adjacenthorizontal lines of luminance signal from three successive fieldintervals; and means for combining the first, second and third luminancesignals in the relation (x_(i) -(A_(i) +B_(i))/2) to generate a temporaldifference signal representing said first auxiliary signal, where B_(i),x_(i) and A_(i) represent the amplitudes of the first, second and thirdluminance signals respectively.
 4. The system set forth in claim 3wherein said delay means includes means for concurrently providingfourth and fifth luminance signals with said first, second and thirdluminance signals, said fourth and fifth luminance signals representinghorizontal lines, respectively, vertically disposed above and below ahorizontal line represented by said second luminance signal, and whereinsaid means for providing said second auxiliary signal includes:means forcombining said second, fourth and fifth signals in the relationship(x_(i) -(C_(i) +C_(i+1))/2) to produce a vertical difference signal,where C_(i) and C_(i+1) represent the amplitudes of the fourth and fifthluminance signals respectively; and means responsive to said firstauxiliary signal and said vertical difference signal for producing saidsecond auxiliary signal exhibiting first and second states when themagnitude of the first auxiliary signal is greater and lesser than themagnitude of the vertical difference signal respectively.
 5. The systemset forth in claim 4 wherein said means for providing said secondauxiliary signal further includes means for compressing said secondauxiliary signal exhibiting first and second states.
 6. The system setforth in claim 1 wherein said source provides a progressive scanluminance signal and said means for providing encoded video signalprovides interlace scan video signals and wherein said means forproviding said first auxiliary signal includes:means responsive to saidprogressive scan luminance signal for generating a temporally differencesignal representing the difference between progressive scan luminancesignal representing a first horizontal line in a first field and theaverage of progressive scan luminance signal from temporally adjacentsecond and third horizontal lines in second and third fields,respectively, disposed before and after said first field; meansresponsive to said progressive scan luminance signal for generating avertical difference signal representing the difference between saidfirst horizontal line and the average of progressive scan luminancesignals representing fourth and fifth horizontal lines in said firstfield and vertically disposed on either side of said first horizontalline; means for comparing said vertical and temporal difference signalsfor providing said first auxiliary signal exhibiting first and secondstates when the magnitude of said temporal difference signal is greaterand lesser than the magnitude or said vertical difference signalrespectively; and wherein said means for providing a second auxiliarysignal includes means responsive to said first auxiliary signal forselectively providing, as said second auxiliary signal, the vertical ortemporally difference signal having the smaller magnitude.
 7. The systemset forth in claim 6 wherein said means for providing said firstauxiliary signal further includes means for compressing said firstauxiliary signal exhibiting first and second states; and wherein saidmeans for providing said second auxiliary signal further includes meansfor compressing said selectively provided vertical and temporallydifference signals.
 8. The system set forth in claim 6 wherein saidfirst auxiliary signal is in single bit digital sample format and saidvertical and temporally difference signals are in multibit digitalsample format, and said means for providing said second auxiliary signalfurther includes means for appending said single bit digital samples ofsaid first auxiliary signal to respective corresponding multibit samplesof said selected vertical or temporally difference signal.
 9. The systemset forth in claim 1 further including a receiver, for receiving saidtelevision signal, comprising:separating means, responsive to receivedtelevision signal, for separating said encoded video signal and saidauxiliary output signal; video signal decoding means, responsive to saidencoded video signal for generating an interlace scan luminance signal;auxiliary signal decoding means, responsive to separated auxiliaryoutput signal, for recognizing said first and second auxiliary signalsand providing a decoded auxiliary signal; and means, responsive to saidinterlace scan luminance signal and said decoded auxiliary signal forgenerating a progressive scan luminance signal.
 10. A video signalprocessing system for processing a television signal including anencoded video signal having luminance and chrominance components ininterlace scan format and including an auxiliary signal transmitted inalternative signal formats, said system comprising:a source of saidtelevision signal; separating means responsive to said television signalfor providing separated encoded video and auxiliary signals; videosignal decoding means responsive to said separated encoded video signalfor providing an interlace scan luminance signal; auxiliary signaldecoding means responsive to said separated auxiliary signal, fordecoding said alternative auxiliary signal formats and providing adecoded auxiliary signal; and a progressive scan processor, responsiveto said interlace scan luminance signal and said decoded auxiliarysignal for generating a progressive scan luminance signal.
 11. Theprocessing system set forth in claim 10 wherein said alternative signalformats of said auxiliary signal include a first signal formatrepresenting a bistate signal which indicates whether said progressivescan processing means will generate additional scan lines moreaccurately by vertical or temporally interpolation and a second signalformat includes an analog signal representing differences between theactual signal values of said additional lines and temporallyinterpolated lines, and wherein said auxiliary signal decoding meansincludes:means, responsive to said separated auxiliary signal, fordetecting said first and second alternative signal formats; and means,responsive to said detecting means and said separated auxiliary signal,for conditioning said auxiliary signal for application to saidprogressive scan processing means.
 12. The system set forth in claim 11wherein said progressive scan processing means includes:interpolatingmeans, responsive to said interlace scan luminance signal forconcurrently providing vertical and temporal estimates of signalrepresenting additional horizontal lines; multiplexing means, responsiveto a control signal for selectively providing either said vertical orsaid temporal estimates; signal combining means having a first inputterminal coupled to said multiplexing means, an output terminal and asecond input terminal; signal speed up circuitry, coupled to the outputterminal of said signal combining means for time compressing interlacescan line intervals of signal to progressive scan line intervals ofsignal; and wherein said means for conditioning said auxiliary signal,includes: means responsive to said detecting means for selectivelycoupling signal representing said second signal format or a zero valuesignal to the second input terminal of said signal combining means whenthe second and first signal formats are detected respectively, andproviding a control signal to said multiplexing means to condition saidmultiplexing means to provide temporally estimates when said secondsignal format is detected; and means responsive to said separatedauxiliary signal, for providing as a control signal to said multiplexingmeans, signal representing said first signal format when said firstsignal format is detected.
 13. The processing system set forth in claim10 wherein said alternative signal formats of said auxiliary signalinclude a first signal format representing a bistate signal whichindicates whether said progressive scan processing means will generateadditional scan lines more accurately by vertical or temporallyinterpolation, and a second signal format includes a signal representingsamples of the smaller of vertical and temporally differences betweenactual signal values of said additional lines and correspondingvertically and temporally interpolated lines with said bistate signalappended to said samples to indicate whether the sample is a vertical ortemporal difference, and wherein said auxiliary signal decoding meansincludes:means responsive to said separated auxiliary signal fordetecting said first and second alternative signal formats; and meansresponsive to said detecting means and said separated auxiliary signal,for conditioning said separated auxiliary signal for application to saidprogressive scan processing means.
 14. The system set forth in claim 13wherein said progressive scan processing means includes:interpolatingmeans, responsive to said interlace scan luminance signal forconcurrently providing vertical and temporal estimates of signalrepresenting additional horizontal lines; multiplexing means, responsiveto a control signal for selectively providing either said vertical orsaid temporal estimates; signal combining means having a first inputterminal coupled to said multiplexing means, having an output terminaland a second input terminal; speed up circuitry coupled to the outputterminal of said signal combining means for time compressing interlacescan intervals of signal to progressive scan intervals of signal; andwherein said means for conditioning said auxiliary signal includes:means responsive to said detecting means and said separated auxiliarysignal for coupling a signal representing said first signal format tosaid multiplexing means as said control signal and applying a zero valueto the second input terminal of said signal combining means when saidfirst signal format is detected; and means responsive to said detectingmeans and said separated auxiliary signal, for separating said appendedbistate signal from said vertical and temporal difference samples ofsaid second signal format and coupling a signal representing saidbistate signal, as a control signal to said multiplexing means, andcoupling signal representing said vertical and temporal samples to thesecond input terminal of said signal combining means, when said secondsignal format is detected.